Related Party Transactions - Additional Information (Detail) (USD $) In Millions, except Share data, unless otherwise specified	1 Months Ended	9 Months Ended				3 Months Ended		9 Months Ended
	Apr. 30, 2010	Sep. 30, 2012	Sep. 30, 2011	Jun. 30, 2012	Apr. 08, 2010	Sep. 30, 2012 Litigation Related To 2009 Exchange Offer [Member]	Jun. 30, 2012 Litigation Related To 2009 Exchange Offer [Member]	Sep. 30, 2012 Litigation Related To 2009 Exchange Offer [Member]
Related Party Transaction [Line Items]
Reimbursement Agreements termination period by either party		90 days
Net activity under reimbursement agreement		$ 3.3	$ 0.3
Cost reimbursed by related party		18.0
Partial pre-payment for premiums related to the D&O Insurance Program		14.6
Insurance program renewal term period		January 31, 2012 through January 31, 2017
Insurance Program Renewal Period		5 years
Costs reimbursable under reimbursement agreement		0.6
Number of shares owned by related party				1,013,000	8,233,526
Series A Preferred Stock, issued and outstanding	9.20%
Total expected cash payments to settle all actions								36.9
Total expected cash payments to settle all actions covered by insurance								23.5
Future payments		5						5
Cumulative charge						$ 2.2	$ 6.7	$ 8.9